Project Summary/Abstract There has been a shift to greater use of neadjuvant chemotherapy (NACT) in the clinical management of cancer. Often used in breast cancer to provide systemic treatment for possible or apparent metastatic disease, NACT also reduces the primary tumor size and facilitates breast conservation. Quantitative magnetic resonance imaging (qMRI) is an effective diagnostic for monitoring tumor regression. There are many methodologies being developed for monitoring cancer in vivo, including contrast agent washout, volumetry, and more recently correlating apparent diffusion coefficients and proton relaxation times to tumor staging. Such imaging biomarkers are predictive of the pathological complete response (pCR) outcome prior to surgery. This enables physicians to provide ?evidence based? treatment modifications to reduce deleterious side effects and improve patient outcomes. To obtain quantitative data from MR images, the variations that occur in imaging as a result of hardware and software differences between MRI manufacturers and day-to-day operations must be quantified. In MRI, the data depends on the protocols used to acquire the image, resulting in inconsistencies if even one parameter in the protocol changes. The goal of the proposed work is to produce and develop and disseminate a ground truth physical standard and quality control program for comparison of MRI scanners in the multisite I-SPY2 (ACRIN 6698) trials monitoring pre-operative chemotherapy treatments in the reduction of tumor size. The physical standard is an anthropomorphic breast phantom capable of fitting into all commercial breast coils. It contains novel human tissue mimics and geometric standards with values traceable to the National Institute of Standards and Technology (NIST). Analysis software capable of protocol compliance checks, rapid identification of the regions of interest, and comparison to ground truth values as measured by NIST will be developed to complement the physical standard. This will enable qualification of sites and quantification of error resulting from scanner performance alone. Given the wide breadth of parameter space that MRI protocols encompass, part of the proposed effort will include the development of protocols specific to image acquisition of tumor volumes and for measuring the apparent diffusion coefficient within the tumor volumes as compared to surrounding healthy tissue.